1. Field of the Invention
The present invention relates to lamps and, in particular, to lamps of the type with replaceable bulb capsules.
2. Description of the Prior Art
This invention is an improvement of the lamp disclosed in U.S. Pat. No. 4,816,977. That lamp has a globe with a cylindrical metal mounting shell fixed to its open end. A removable base structure includes a ceramic socket with holes containing spring contacts which respectively receive the contact pins of a replaceable bulb capsule having a ceramic base. The removable base structure, with the bulb capsule mounted thereon, is then insertable through the open end of the globe. Tabs on the mounting shell slide in grooves on the socket wall to align the parts. Leaf springs projecting laterally from the socket engage a radially extending annular flange on the mounting shell to latch the parts together. The base structure includes a separate threaded cap which fits over one end of the socket and is fixed thereto.
In order to remove the removable base structure from the globe for the purpose of replacing the bulb capsule, it is necessary to simultaneously grasp and compress the leaf springs, which is sometimes difficult to do. Furthermore, the spring contacts, which are subjected to considerable heat, tend to fail over time. Also, the ceramic socket is exposed and may be subject to cracking or the like if it strikes surrounding objects. Finally, the bulb capsule with the ceramic base is relatively expensive.